Fever Patterns - Differential Diagnosis Framework Continuous Fever: Temp > 38°C with only 1 degree fluctuation in 24 hours • Viral and bacterial infections • Typhoid fever (Step ladder: fever plateaus at 103-104°F) • Lobar pneumonia • Rickettsial diseases • Brucellosis • Typhus, gram-negative pneumonia • Acute bacterial meningitis Remittent Fever: Temp > 38°C with fluctuation more than 2°C in 24 hours • Viral infections • Acute bacterial endocarditis • Typhoid fever • Rickettsiae infections Intermittent Fever: High spike and rapid resolution falling to normal • Pyogenic/focal infection • Abscess, bacteremia • Malaria • Lymphoma • TB • Juvenile idiopathic arthritis • Infective endocarditis, malaria • Leptospira • Borrelia, schistosomiasis • Pyemia Malarial Intermittent Fevers: • Intermittent tertian: P. vivax & ovale • Intermittent subtertian: P. falciparum • Quotidian (daily): P. knowlesi Double Quotidian Fever: 2 distinct daily peaks of fever • Visceral leishmaniasis • Adult Still's • Gonococcal endocarditis Other Recurrent Fevers: • Still's disease • Crohn disease • Behcet disease • Drug fever • Factitious fever Periodical Fever: Periods with low-grade fever or no fever • Malaria • Lymphoma • Borrelia • Rat-bite fever Fever months/years without bacterial/viral source Non-Infectious Causes: • Still's disease • Rheumatoid arthritis • Crohn's disease • Behcet's syndrome • Cyclic neutropenia Typhus Inversus Pattern: Reversal of the usual diurnal pattern (Temp high in AM > PM) • Disseminated tuberculosis • Typhoid fever • Polyarteritis nodosa • Endocarditis • Hepatic abscess Hereditary Periodic Fever: • Familial Mediterranean fever • Hyper-IgD syndrome • Tumor necrosis factor receptor-associated periodic syndrome Biphasic Fever: • Dengue fever • Leptospirosis Pel-Ebstein Fever: Fever 1-2 weeks followed by an afebrile period of 1-2 weeks • Hodgkin lymphoma Relapsing Fever: Fever followed by an afebrile period of several days • Tick-borne relapsing fever • Louse-borne relapsing fever Undulant Fever: Temperature rises gradually and falls (like a wave) over days to weeks • Brucellosis Faget's Sign - Temperature Pulse Dissociation: For every 1°F rise in temp, HR incrementally increases by 8-10 bpm (Liebermeister’s rule) Fever Associated with Relative Bradycardia: • Legionnaire's disease • Chlamydia • Salmonella typhi (typhoid fever) • Dengue • Babesiosis • Leishmaniasis • Brucellosis • Psittacosis • Mycoplasma pneumonia • Yellow fever • Tuberculous meningitis • Blackwater fever (Falciparum malaria with profound hemolysis) • Malaria • Leptospirosis • Viral hemorrhagic fevers Fever + Night Sweats: • TB • Nocardia • Brucellosis • Liver or lung abscess • Sub-acute infective endocarditis Non-Infectious Diseases: • Polyarteritis nodosa • Lymphomas #Fever #Patterns #Differential #Diagnosis #intermittent #periodic #infections
